Midlands Air Ambulance charity's headquarters raided
The Midlands Air Ambulance's headquarters have been raided by three masked men armed with a stun gun.
Police said the men burst into the charity's office on the Enterprise Trading Estate, off Pedmore Road, in Brierley Hill at around 0845 BST.
An ambulance spokesman said they held 20 members of staff hostage with the stun gun although it was not used on them.
No-one was injured, and the men escaped in a member of staff's car having stolen bags of money.
Acting Det Sgt Chris Woodward said: "This is a serious and despicable crime.
"Staff had not long arrived at work when they were confronted with these men in the office.
"They were threatened by the men and had phones taken off them.
"The offenders then took money bags containing cash that had been donated. As yet we do not have a definite amount that has been stolen, however we believe the sum to be significant.
"Thankfully no-one was hurt, however all those involved were obviously upset and shaken by their ordeal."
He said the stolen car was a grey Peugeot 308 and they were appealing for anyone who had seen one in the area after around 0915 BST to come forward.
He added the vehicle had not yet been found.
Midlands Air Ambulance charity director Hanna Sebright said: "I find it hard to comprehend that people would commit such a violent crime and steal money from a life-saving charity.
"Dedicated people have gone to great lengths to raise money for the charity, and it is appalling that it will be unable to be used for the purpose of keeping the air ambulances in the air.
"This despicable act could actually cost people's lives."
Police said the men are all described as black, in their 20s and wearing scarves across their faces.